Aeromagnetic and Radio Echo Ice-Sounding Measurements Show Much Greater Area of the Dufek Intrusion, Antarctica

A combined aeromagnetic and radio echo ice-sounding survey made in 1978 in Antarctica over the Dufek layered mafic intrusion suggests a minimum area of the intrusion of about 50,000 square kilometers, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and s...

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Bibliographic Details
Published in:Science
Main Authors: Behrendt, John C., Drewry, David J., Jankowski, Edward, Grim, Muriel S.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 1980
Subjects:
Dufek Massif
Forrestal Range
Antarc*
Antarctica
ice covered areas
Online Access:http://dx.doi.org/10.1126/science.209.4460.1014
https://www.science.org/doi/pdf/10.1126/science.209.4460.1014
Description
Summary:A combined aeromagnetic and radio echo ice-sounding survey made in 1978 in Antarctica over the Dufek layered mafic intrusion suggests a minimum area of the intrusion of about 50,000 square kilometers, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and subglacial topographic profiles illustrate the usefulness of this combination of methods in studying bedrock geology beneath ice-covered areas. Magnetic anomalies range in peak-to-trough amplitude from about 50 nanoteslas over the lowermost exposed portion of the section in the Dufek Massif to about 3600 nanoteslas over the uppermost part of the section in the Forrestal Range. Theoretical magnetic anomalies, computed from a model based on the subice topography fitted to the highest amplitude observed magnetic anomalies, required normal and reversed magnetizations ranging from 10 -3 to 10 -2 electromagnetic units per cubic centimeter. This result is interpreted as indicating that the Dufek intrusion cooled through the Curie isotherm during one or more reversals of the earth's magnetic field.

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